Rubber products



Patented Sept. 8, 3936 v UNITED STATES PATENT OFFICE RUBBER PRODUCTS Harry Ben Dykstra, Wilmington, Del., assignor to. E. I. du Pont de Nemours & Company, Wilmington, Del., a corporation of Delaware No Drawing. Application April 51934, Serial No. 719,148 v 15 Claims. (01. 260-1) This invention relates to new rubber derivatives and one mole of chloromethyl ether. The resultand more particularly to new rubber derivatives lngproduct was light tan in color, only slightly prepared by th dditi of t i ti e halogen extensible, and insoluble in the usual rubber solcompounds t rubb r, vents such as chloroform and benzene, and like- Exa le of t simple dditio of organic omwise insoluble in solvents such as alcohol and 5 pounds to rubber are relatively rare. Alkyl or one. aryl sulfur halides, for example, phenyl sulfur Example 2 v chloride have been added to rubber as disclosed Two hundred d fifty grams of bb d 380 in British. Patent 3131919 and French Patent grams of chloromethyl butyl ether were allowed to 1 5 fifllmbergyin Volume 65, pages 1349 to stand in contact at room temperature (25 C.) in o 54 0f the Beric li def de h chemischen a closed reaction vessel for 17 days. The reaction sellschaft, discloses the addition Of thioglycollic mass was then steam distilled and the rubber deacid to rubber without solvent or catalyst. Geri t dried in vacuo, h t o product, man Patent 557,270 discloses the reaction between contained 75% hl i as compared ith a t rubber and benzyl chloride in carbon tetrachloride ti value of 135% chlorine for m t with Such Cata y 85 aluminum Chlorideaction of one mole of .chloromethyl butyl ether This invention has as an O j t t p p and one mole of rubber. The product was tancoltion ofv new derivatives of, rubber. A further Obored, practically non-extensible and insoluble in .iect is the prepara f new Substances useful the usual organic solvents, although some swelling 20 in plastic and adhesive compositions. Further occurredin rubber solvents.

objects will appear hereinafter. Emmple 3 These objects are accomplished by the follow- 1 ing invention wherein rubber is reacted with an Forty'six grams of acetyl chloride and 10 grams organic compound such as an alpha halogenated of rubber in the form of thin strips were allowed to ether or an acid chlofldey eontaining a halogen react in a suitable flask for 3 weeks at 25 C. The 26 ate-m attached to carbon direetlyattached to an excess acid chloride was then destroyed with hot water and the product dried in vacuo. This deoxygen atom.

In general, in the process of the present i rlvative conta ned 17.2% chlorine as compared tion the rubber in the form of thin strips or other Wlth theoretlcal Value of 242%; was conslder' ably darker in color as compared with the chloro- 80 pieces affording a large surface area, is mixed with from 1 to 4 moles f the halide per one mo1e ether derivatives and insoluble in rubber or other organic solvents. Here again slight swelling was of isoprene unit of the rubber and allowed to react attemperatures ranging from 20 to 100 C., observed Wlth rubber solvents' but, preferably at 30 C. for an extended time, on Example 4 a the order of two weeks. The reaction may also be carried'out in solution in which event the reigf gi ifigifi gfi 1 g g gt ifgagg b action periodis much shorter, especially where a f th t 1 BC! t catalyst is used. The reaction is conducted in a grams 0 lsmu I m or 1 as alyst reaction vessel from which moisture can be exwere allowed Stat-id for 19 days at 25 {30 eluded. Illustrative but not limitative examples gg mlxtutliae Wasfthent treated mm 40 are given below. successive 7 cc. por ons 0 ho benzene to V I take out unreacted rubber and excess vchloro- Example 1 ether, and finally treated with one 250 cc. portion of alcohol. The insoluble product was then Twent -five rams of rubber in small ieces was covered with 75% grams of chloromethyl ether and ggg vacuum oven' Analysls for chlorme 45 allowed to stand at room temperature (25 C.) gave Example 5 ait: zifa ri d tfi t u g? fi' gggf g S x grainsof chloromethyl ether and 2.5 grams strong odor of chloromethyl ether, was steam dis-' 2% 2 336 9? g gizg gi gl 221 9 gg z tilled to destroy the unreacted chloroether. dried t d d th l a for 3 hours in vacuo and then for 48 hours in a i g g i; ain rymg i Fm g cred dessicator containing potassium hydroxide. Chloso u e m er enva We was 0 mm rine analysis gave an average of 16% chlorine as Example 6 compared with 24% chlorine for the complete re- Ninety-two grams of an 18.5% solution 01' rubaction of one mole of rubber (calculated as C5Hs), her in petroleum ether and 45 grams of chlo'rozene and again precipitated with acetone.

Example 7 To a solution of 50 grams pale crepe (rubber) in 950 grams petroleum ether, 78 grams acetyl chloride and 133 grams aluminum chloride were added with stirring. An exothermic reaction occurred, making it necessary to apply external cooling to keep the temperature below 30 C.-

The mixture was stirred for four hours at 20 to 30 C. The mass was treated with water and extracted with benzene. On removing the benzenlg from the extract by vacuum distillation, the e was obtained 66 grams of dark-colored, rubber-like resin, containing only 0.19% chlorine. This product was readily soluble in ethyl acetate, butyl acetate, and in aromatic hydrocarbons, yielding solutions of relatively low viscosities. Films cast from these solutions were fast drying, fairly hard, but somewhat brittle. The rubber-acetyl chloride condensation prodnot obtained in this experiment was compatible with meta styrene and with polyhydric alcoholpolybasic acid resins of the oil-modified type. It could also be used in a limited ratio with other resins, and with oils, cellulose derivatives, etc.

In place of the chloromethyl ether and chloromethyl butyl ether given in the foregoing examples, other alpha halogenated others such as .chloromethyl ethyl ether, di-(chloromethyD- ether, bromomethyl ethyl ether, alpha chloroethyl ethyl ether, alpha chloroethyl phenyl ether, chloromethyl propyl ether, alpha chloroethyl dodecyl ether, chloromethyl octadecyl ether, chloromethyl cyclohexyl ether, etc. may be used. Propionyl chloride, toluyl chloride, naphthoyl chloride, butyryl chloride, lauric acid chloride, benzoyl chloride, etc., may be substituted for the acetyl chloride given in Examples 3 and 7. Other similar halides such as acetyl bromide or iodide may be used. The reaction of rubber with acid halides gives, in addition to halogen containing rubber derivatives, also substantially halogenfree rubber derivatives which appear to have a ketone structure; similarly, substantially halogen-free products may be obtained from the ether condensation.

As illustrated in the examples, the reaction may be carried out with or without the presence of an inert solvent. Solventsmay be any mutual solvents such as petroleum ether, chloroform,

carbon tetrachloride, cyclohexane, which will not react with rubber or the chlorine compound. Without an inert solvent for each mole of rubber the experiments included from one to four moles of the chloro compound. However, a large excess of the chloro ether or acid chloride may be used without ill effects and in general, the greater the excess of chloro derivative the more rapid the reaction. Thus, for one mole of rubber and two moles of chloro ether, the reaction after two weeks at room temperature had progressed about half as far as a similar reaction wherein four moles of chloro ether had been used per isoprene unit of the rubber.

The temperature of the reaction may be varied from 20 to 100 C. under ordinary conditions.

The limiting temperature at atmospheric pressure is necessarily limited by the boiling point of the chloro derivative or the solvent, if a solvent is .used. By the use E'of a closed reaction vessel capable or withstanding pressure the tempera ture may be raised considerably above the atmospheric boiling points of any of the components of the reaction mixture without harmful effects and with a considerably increased speed of reaction. The reaction vessel may be fashioned of glass, porcelain, acid resistant metal, enamellined metal, etc. Because of the reactivity towards moisture of the active halogen compounds used in the reaction, it is desirable that moisture, and, therefore, air, be excluded. The reaction vessel may thus be sealed for low temperature reactions or may be connected, in the case of high temperature reactions, to a drying train containing any of the well known drying agents, for example, calcium chloride or sulfuric acid.

Certain of the examples disclose the use of catalysts. Catalysts of the Friedel and Crafts type may be used.

Thus, aluminum chloride, ferric chloride, stannic chloride, and bismuth chloride may be used. It is preferred to use bismuth chloride in an amount of about 1% based on the weight of rubber used.

The soft products obtained by incomplete reaction may be used as adhesives for binding rubber to metal, wood, etc., and, together with pigments, plasticizers, fillers, etc., in molding compositions. The harder materials representing a more nearly completed reaction may be cut or machined into useful articles. The inertness of the ether derivatives prepared by the process of Examples 1, 2, 4, 5 and 6 towards all solvents tried, indicates their usefulness as gaskets or as fillers for use where exposure to hot oil or solvent is encountered and as replacements for rubber articles which would be swelled by such exposure. The soluble derivatives prepared with the use of a larger amount of catalyst as in Example 7 may be used with the customary dyes,

. tended to'be illustrative only. Any modification of or variation therefrom which conforms to the spirit of the invention is intended to be included within the scope of the claims.

I claim: I

1. The process which comprises reacting rubber with a chloromethyl ether.

2. The process which comprises reacting rubber with a chloromethyl ether in an inert solvent.

3. The process which comprises reacting one part rubber with approximately three and onehalf parts of chloromethyl butyl ether in the presence of about 0.01 part of bismuth trichloride for about 19 days at 25 to 30 C., and extracting the reaction product with benzene and alcohol to remove unreacted material.

4. The process which comprises reacting rubber with a chloromethyl ether in the presence of bismuth chloride.

5. As new products, reaction products of rubber with an alpha halogenated ether wherein the halogen is of the class consisting of chlorine and bromine and not more than one halogen atom is attached to either of the carbon atoms alpha to the ether oxygen atom.

6. As new products,-chloromethyl ether-rubber reaction products.

7. The process which comprises reacting rubber with an alpha halogenated ether of the class consisting of alpha monochlorinatecl and alpha. monobrominated ethers.

8. The process which comprises reacting rubber in the presence of a catalyst with an alpha halogenated ether of the class consisting of alpha. monochlorinated and alpha. monobrominated others.

9. As new products, reaction products of rubber with an alpha halogenated ether of the class consisting of alpha monochlorinated and alpha monobrominated ethers.

10. As new products chloromethyl butyl etherrubber reaction products.

11. As new products reaction products of rubber with an alpha chlorinated ether wherein not more than one chlorine atom is attached to either of the carbon atoms alpha to the ether oxygen carries one and only one chlorine atom.

12. The process which comprises reacting rubber with an alpha halogenated ether wherein the halogen is of the class consisting of chlorine and bromine and not more than one halogen atom is attached to either of the carbon atoms alpha to the ether oxygen atom.

13. The process which comprises reacting rubber with an alpha halogenated ether wherein the halogen is of the class consisting of chlorine and bromine and not more than one halogen atom is attached to either of the carbon atoms alpha to the ether oxygen atom in the presence or a catalyst.

14. The process which comprises reacting rubber with an alpha halogenated ether wherein the halogen is of the class consisting of chlorine and bromine and not more than one halogen atom is attached to either of the carbon atoms alpha to the ether oxygen atom in the presence of an inert solvent.

15. The process which comprises reacting rubber with an alpha halogenated ether wherein the halogen is of the class consisting of chlorine and bromine and not more than one halogen atom is attached to either of the carbon atoms alpha to the ether oxygen atom in the presence of bismuth chloride.

HARRY BEN DYKSTRA. 

